JP7253575B2 - Ship fuel supply system and fuel supply method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a fuel supply system and a fuel supply method for ships using incompressible fluid as engine fuel.

In general, petroleum gas is produced at a production site in the state of liquefied petroleum gas (LPG), which is liquefied at a low temperature, and then transported to a destination over a long distance by an LPG carrier.

Oil fuel such as HFO (Heavy Fuel Oil) or MDO (Marine Diesel Oil) is used as engine fuel in conventional LPG carriers. In addition, conventional LPG carriers store and transport LPG as cargo in storage tanks. Transferred to tanks and stored.

Thus, in conventional LPG carriers, fuel and cargo are used or processed in two systems, and there is no means, such as an engine, that can use LPG stored in storage tanks as cargo as fuel. In recent years, there has been an increasing interest in supplying LPG, which is stored as cargo in storage tanks, as engine fuel.

WO2018/189927

When the excess fuel discharged from the engine is returned to the storage tank, the liquefied gas in its liquid state is decompressed and a large amount of flash gas is generated.

In order to prevent the internal pressure of the storage tank from increasing due to flash gas generated when surplus fuel discharged from the engine is returned to the storage tank, the present invention reduces the pressure after the surplus fuel is discharged from the engine and mixes gas and liquid. To provide a fuel supply system and a fuel supply method for ships, in which surplus fuel in two phases is separated by a gas-liquid separator and the separated fluid is sent to a storage tank.

In order to achieve the above object, in one embodiment of the present invention, there is provided a first pressure reducing device for reducing the pressure of excess fuel discharged from an engine, and a gas-liquid mixed fluid decompressed by the first pressure reducing device. and a gas-liquid separator that separates into phases, the gas separated by the gas-liquid separator is returned to the storage tank, and the excess liquefied gas is supplied to the engine as fuel before being used in the engine. There is provided a marine fuel supply system, characterized in that surplus fuel that has not been discharged from the engine is discharged from the engine and supplied to the first pressure reducing device.

Preferably, the liquefied gas separated by the gas-liquid separator is combined with the liquefied gas discharged from the storage tank.

Preferably, the first pressure reducing device reduces the pressure of excess fuel discharged from the engine to the pressure of the liquefied gas discharged from the storage tank.

Further comprising a second decompression device for decompressing the gaseous state gas separated by the gas-liquid separator, the storage tank after decompressing the gaseous state gas separated by the gas-liquid separator by the second decompression device preferably sent to

Preferably, the liquefied gas separated by the gas-liquid separator is sent inside the storage tank.

Preferably, the first pressure reducing device reduces the pressure of excess fuel discharged from the engine to the internal pressure of the storage tank.

It is preferable that the marine fuel supply system further includes a first pump installed inside the storage tank for discharging the liquefied gas stored in the storage tank to the outside of the storage tank.

Preferably, the marine fuel supply system further comprises a second pump for pressurizing the liquefied gas discharged from the storage tank and supplied to the engine to a pressure required by the engine.

Preferably, the liquefied gas separated by the gas-liquid separator is combined with the liquefied gas discharged from the storage tank upstream of the second pump and used again as fuel for the engine.

A valve is preferably installed on a line through which the liquefied gas separated by the gas-liquid separator is discharged.

It is preferable to further include a heater for heating the liquefied gas discharged from the storage tank and supplied to the engine to a temperature required by the engine.

In another embodiment of the present invention for achieving the above object, there are provided: 1) after supplying excess liquefied gas to an engine as fuel, exhausting excess fuel remaining unused in the engine from the engine; 2) depressurizing the surplus fuel discharged from the engine in step 1); and 3) separating the gas-liquid mixed fluid depressurized in step 2) into a gas phase and a liquid phase. and 4) returning the gaseous gas separated in step 3) to a storage tank, and supplying the liquefied gas discharged from the storage tank as fuel to the engine. A fueling method for a marine vessel is provided.

In one embodiment of the present invention, the gas-liquid mixed fluid is not supplied to the storage tank, but only the gas in the gaseous state separated by the gas-liquid separator is supplied. Therefore, the generation of flash gas due to the pressure reduction of the liquefied gas in the liquid state is suppressed, and the pressure inside the storage tank can be easily controlled.

Further, in one embodiment of the present invention, the gas-phase gas and the liquid-state liquefied gas separated by the gas-liquid separator are separately supplied without supplying the gas-liquid mixed fluid to the storage tank. Since the liquefied gas in the liquid state is decompressed to the internal pressure of the storage tank, the generation of flash gas due to the decompression of the liquefied gas in the liquid state is suppressed, and the internal pressure of the storage tank can be easily controlled. can do.

Furthermore, in one embodiment of the present invention, the liquefied gas in the liquid state separated by the gas-liquid separator is combined with the liquefied gas discharged from the storage tank and sent to the second pump, so that it is pressurized by the first pump. This has the advantage that the flow rate of liquefied gas can be reduced and the power consumption of the first pump can be reduced.

1 is a schematic diagram of a marine fuel supply system according to a first embodiment of the present invention; FIG. It is a schematic diagram of a fuel supply system for ships concerning a 2nd embodiment of the present invention.

Hereinafter, configurations and actions of embodiments of the present invention will be described in detail with reference to the drawings. The following embodiments can be modified into other various forms, and the scope of the technical idea of the present invention is not limited by the following embodiments.

FIG. 1 is a schematic diagram of a marine fuel supply system according to a first embodiment of the present invention.

Referring to FIG. 1, the marine fuel supply system of the present embodiment includes a first pressure reducing device (50) for reducing the pressure of surplus fuel discharged from an engine (E), and pressure reduction by the first pressure reducing device (50). and a gas-liquid separator (60) for separating the mixed gas-liquid fluid into a gas phase and a liquid phase.

The storage tank (T) of this embodiment stores liquefied gas, and the liquefied gas discharged from the storage tank (T) is supplied to the engine (E) as fuel. A first pump (10) is installed inside the storage tank (T) to pump the liquefied gas and discharge it to the outside of the storage tank (T).

In this embodiment, after supplying excess liquefied gas to the engine (E) as fuel, when the remaining fuel not used in the engine (E) is discharged from the engine (E), it is discharged from the engine (E) The surplus fuel thus produced is sent to the first pressure reducing device (50).

When supplying gaseous compressible fluid as fuel for the engine (E), the fuel supply line (F1) can be filled with a slightly higher pressure than required by the engine (E). , the fuel, which is a compressible fluid, is present in the fuel supply line (F1) in a somewhat compressed state. As a result, even if the engine (E) suddenly needs a large amount of fuel, the fuel can be supplied immediately, so even if the load of the engine (E) fluctuates, the fuel can be stably supplied. can.

However, when incompressible fluid in a liquid state is supplied as fuel for the engine (E), the change in volume of the incompressible fluid is negligible even when pressure is applied, so the fuel supply line ( No method can be used to keep F1) filled at a slightly higher pressure than required by the engine (E).

Furthermore, when the engine (E) suddenly requires a large amount of fuel, the required amount of fuel cannot be supplied to the engine (E), and cavitation occurs in the engine (E). There is fear.

Therefore, the inventors of the present invention have determined that it is better to supply more fuel than is needed by the engine, rather than creating a case where the engine (E) runs out of fuel.

In this embodiment, instead of supplying only the amount of liquefied gas required by the engine (E) to the engine (E), a sufficient amount of liquefied gas that can cope with the load fluctuation of the engine (E) is supplied to the engine (E ), and the excess liquefied gas remaining unused in the engine (E) is discharged from the engine (E).

Therefore, according to the present invention, fuel can be stably supplied to the engine even when the incompressible fluid in the liquid state is supplied as the engine fuel.

In this embodiment, about 100% to 120% of the liquefied gas required by the engine (E) is supplied to the engine (E), preferably about 110% of the required amount of liquefied gas is supplied to the engine (E). (E).

As the first decompression device (50) of the present embodiment, various means for decompressing a liquid can be applied. For example, the first decompression device (50) is preferably a Joule-Thomson valve.

The gas-liquid separator (60) of the present embodiment separates the surplus fuel, which has been discharged from the engine (E) and has been decompressed by the first decompression device (50) into a gas-liquid mixture state, as a gaseous state gas. It separates into liquid state liquefied gas.

The gaseous state gas separated by the gas-liquid separator (60) is returned to the storage tank (T), and the liquid state liquefied gas separated by the gas-liquid separator (60) is returned to the storage tank (T). and the liquefied gas discharged from the engine (E) is used again as fuel for the engine (E).

A valve (V) is installed on the line through which the liquefied gas separated by the gas-liquid separator (60) is discharged, and the water level of the liquefied gas collected inside the gas-liquid separator (60) is within a predetermined range. The opening and closing of the valve (V) is adjusted to maintain at .

The marine fuel supply system of this embodiment includes a second pump (20) for pressurizing the liquefied gas supplied to the engine (E) after being discharged from the storage tank (T) to the required pressure of the engine (E). and/or a heater (40) for heating the liquefied gas supplied to the engine (E) after being discharged from the storage tank (T) to the required temperature of the engine (E).

The heater (40) of this embodiment heats the liquefied gas to about 40°C to 50°C, preferably to about 45°C.

When the liquefied gas separated by the gas-liquid separator (60) is combined with the liquefied gas discharged from the storage tank (T), the first pressure reducing device (50) removes the liquefied gas discharged from the storage tank (T). The pressure (i.e. the pressure at the junction, the pressure of the liquefied gas pumped by the first pump (10) if a first pump (10) is provided, the second pump (20) if a second pump (20) is provided Preferably, the liquefied gas is decompressed to the upstream pressure of the gas before being sent to the gas-liquid separator (60). Further, the gaseous state gas separated by the gas-liquid separator (60) is sent to the storage tank (T) after being decompressed to the internal pressure of the storage tank (T) by the second decompression device (70). is preferred.

Various means for decompressing a liquid can be applied as the second decompression device (70) of the present embodiment. For example, the second decompression device (70) is preferably an expansion valve such as a Joule-Thomson valve. . Also, the pressure of the fluid decompressed by the second decompression device (70) is about 15 bar to 20 bar, preferably about 19 bar.

In this embodiment, since only the gaseous gas separated by the gas-liquid separator (60) is supplied without supplying the gas-liquid mixed fluid to the storage tank (T), the liquefied gas in the liquid state is supplied. Generation of flash gas due to pressure reduction is suppressed, and the internal pressure of the storage tank (T) can be easily controlled.

Further, when the present embodiment includes both the first pump (10) and the second pump (20), the liquefied gas in the liquid state separated by the gas-liquid separator (60) is discharged from the storage tank (T). By joining the liquefied gas and sending it to the second pump (20), the flow rate of the liquefied gas pressurized by the first pump (10) can be reduced. As a result, there is an advantage that the power consumption of the first pump (10) can be reduced compared to the case where the first pump (10) pumps all the required flow rate.

FIG. 2 is a schematic diagram of a marine fuel supply system according to a second embodiment of the present invention.

The marine fuel supply system of the second embodiment shown in FIG. 2 differs from the marine fuel supply system of the first embodiment shown in FIG. is sent to the storage tank (T). The following description will focus on the points of difference, and detailed descriptions of the same members as those of the marine fuel supply system of the first embodiment will be omitted.

In this embodiment, the liquefied gas separated by the gas-liquid separator (60) is not combined with the liquefied gas discharged from the storage tank (T) as in the first embodiment, but the storage tank (T) is Preferably, the first pressure reducing device (50) reduces the pressure of the liquefied gas to the internal pressure of the storage tank (T) before sending it to the gas-liquid separator (60). Therefore, in this embodiment, unlike the first embodiment, it is not necessary to additionally install the second decompression device (70).

The pressure of the fluid decompressed by the first decompression device (50) is about 15-20 bar, preferably about 19 bar.

In this embodiment, the gas-liquid gas separated by the gas-liquid separator (60) and the liquefied gas in the liquid state are separately supplied without supplying the gas-liquid mixed fluid to the storage tank (T). . Since the liquefied gas in the liquid state is decompressed to the internal pressure of the storage tank (T), the generation of flash gas due to the decompression of the liquefied gas in the liquid state is suppressed, and the internal pressure of the storage tank (T) can be easily controlled.

It is obvious to those skilled in the art to which the present invention belongs that the present invention is not limited to the above-described embodiments, and that various modifications or changes can be made without departing from the technical scope of the present invention.

Claims (11)

a first decompression device for decompressing surplus fuel discharged from the engine;
returning the gaseous state gas separated by the gas-liquid separator to the storage tank;
After supplying excess liquefied gas to the engine as fuel, the excess fuel remaining unused in the engine is discharged from the engine and supplied to the first pressure reducing device;
A marine fuel supply system , characterized in that the liquefied gas separated by the gas-liquid separator is combined with the liquefied gas discharged from the storage tank. a first depressurizing device for depressurizing excess fuel discharged from the engine;
a gas-liquid separator that separates the gas-liquid mixed fluid decompressed by the first decompression device into a gas phase and a liquid phase;
returning the gaseous state gas separated by the gas-liquid separator to the storage tank;
After supplying excess liquefied gas to the engine as fuel, the excess fuel remaining unused in the engine is discharged from the engine and supplied to the first pressure reducing device;
sending the liquefied gas separated by the gas-liquid separator to the inside of the storage tank;
A marine fuel supply system, wherein the first decompression device decompresses surplus fuel discharged from the engine to an internal pressure of the storage tank. 2. The marine fuel supply system according to claim 1 , wherein said first pressure reducing device reduces the pressure of excess fuel discharged from said engine to the pressure of liquefied gas discharged from said storage tank. further comprising a second decompression device that decompresses the gas in a gaseous state separated by the gas-liquid separator;
4. The marine fuel supply system according to claim 3, wherein the gas separated by the gas-liquid separator is decompressed by a second decompression device before being sent to the storage tank. 3. The ship according to claim 1 , further comprising a first pump installed inside said storage tank for discharging the liquefied gas stored in said storage tank to the outside of said storage tank. fuel supply system for 6. The system according to any one of claims 1 to 5 , further comprising a second pump for pressurizing the liquefied gas discharged from the storage tank and supplied to the engine to a pressure required by the engine. Fuel supply system for ships. The liquefied gas separated by the gas-liquid separator is combined with the liquefied gas discharged from the storage tank upstream of the second pump and used again as fuel for the engine. 7. The marine fuel supply system according to 6 . A marine fuel supply system according to any one of claims 1 to 5 , characterized in that a valve is installed on the line through which the liquefied gas separated by the gas-liquid separator is discharged. The ship according to any one of claims 1 to 5 , further comprising a heater for heating the liquefied gas discharged from the storage tank and supplied to the engine to a temperature required by the engine. fuel supply system for 1) after fueling an engine with excess liquefied gas, exhausting the excess fuel remaining unused in the engine from the engine; and 2) the excess exhausted from the engine in step 1). 3) separating the decompressed gas-liquid mixed fluid in step 2) into a gas phase and a liquid phase; and 4) the gas state separated in step 3). returning the gas from the storage tank to the storage tank, and combining the liquid state liquefied gas separated in step 3) with the liquefied gas discharged from the storage tank;
A fuel supply method for a ship, characterized in that the liquefied gas discharged from the storage tank is supplied as fuel to the engine. 1) after fueling an engine with excess liquefied gas, exhausting excess fuel remaining unused in said engine from said engine;
2) reducing excess fuel discharged from the engine in step 1) to the internal pressure of a storage tank storing liquefied gas;
3) separating the gas-liquid mixed fluid decompressed in step 2) into a gas phase and a liquid phase;
4) returning the gaseous state gas separated in step 3) back to the storage tank, and sending the liquid state liquefied gas separated in step 3) to the inside of the storage tank;
A fuel supply method for a ship, characterized in that the liquefied gas discharged from the storage tank is supplied as fuel to the engine.

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